Acid-type photographic fixer-hardener baths



United States Patent ()flice 3,008,828 Patented Nov. 14', 1 961 V I 3,008,828 ACID-TYPE PHOTOG A HgC FIXER-HARDENER B TH Richard W. Henn and Nancy H. King, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey I No Drawing. Filed May 12, 1958, Ser. No. 734,429 14 Claims. (Cl. 96-61) This invention relates to acid photographic hardener fixing baths. More particularly, it relates to acid photographic hardener fixing baths which can be readily washed out of photographic fihns and papers after fixing.

An acid photographic hardener fixing bath ordinarily contains a hardening agent, a soluble thiosulfate, such as sodium thiosulfate and ammonium thiosulfate, an acid such as acetic acid and a soluble sulfite and/or a soluble bisulfite such as sodium sulfite and sodium bisulfite, which serves to stabilize the soluble thiosulfate in acid solution. The fixing bath may also contain, for example, an additional acid, such as boric acid (crystals).

As known to those skilled in the art, it too much thiosulfate, such as hypo, for example, is allowed to remain in a photographic film or paper, the film; or paper will be detrimentally afiected. Accordingly, when photographic film or paper is treated with a solution (such as an acid fixing bath) containing -a thiosulfate, the film or paper is usually washed with water until substantially all the thiosulfate is removed trom the film or paper.

Acid photographic fixing baths which contain no hardening agent are readily washed out of photographic films and papers. However, the known acid photographic fixing baths which contain a hardening agent do not readily wash out of photographic films and paper.

It is apparent that if the fixing bath solution can be removed from photographic films and papers more rapidly, the time required for photographic processing will be shortened with resultant economy of operation. Accordingly, it is an object. of our invention to provide acid photographic hardener fixing baths having improved wash-out characteristics. A further object is to provide photographic materials of improved stability. I

Ordinarily the quantity of sulfite and/ or bisulfite present in an acid fixing bath (whether it contains a hardening agent or not) is small as compared to the thiosulfate present. Usually. the total amount of sulfite and/or bisulfite present is less than of the weight of the sodium thiosulfate, although we are aware that acid fixing baths having a higher proportion of sulfite and/or bisulfite to sodium thiosulfate are known and are disclosed, for example, in U.S. Patents 1,411,687 and 2,214,216.

We have discovered that if an alkali metal sulfite and/ or alkali metal bisulfite is present in an acid photographic hardener fixing bath in materially increased amount with respect to the thiosulfa'te, the fixing bath has materially improved washout characteristics. Thus, for a given amount of washing, less thiosulfate is retained in photographic films and papers fixed with an acid photographic hardener fixing bath of the presentinvention than-when the acid photographic hardener fixing baths are used. In accordance with our invention, the alkali metal sulfite should be present in the proportion of about 60 to about 150 mole percent per mole of thiosulfate while the alkali metal bisulfite should be present in the proportion of about 120 to about 300 mole percent per mole of thiosulfate. The use of about 75 to about 150 mole percent of the alkali metal sulfite per mole of thiosulfate appears to beadvantageous and is preferred. Similarly, the use of about 150 to about 300 mole percent of the alkali metal bisulfite per mole of thiosulfate appears to be advantageous and is preferred. Higher amounts of the metal sulfite and/or alkali metal bisulfite than stated can be employed but there appears to be no advantage .in using greater amounts of these materials than set forth. In the claims 1 mole percent Otf alkali metal sulfite is considered as being equivalent to 2. mole percent of alkali metal bisulfite. The acid photographic hardener fixing baths of our invention contain about 40 to about 250 grams of sodium thiosulfate (anhydrous) or equivalent amount of another suitable thiosulfate per liter of solution.

As indicated in the preceding paragraph less alkali metal sulfite than alkali metal bisulfite is required. Our tests indicate that there is some loss in emulsion hardness when an alkali metal sulfite is employed. However, the use of an alkali metal bisulfite caused no loss or at most, little loss in emulsion hardness. Thus, in cases where one wishes to avoid loss in emulsion hardness alkali metal bisulfite should be employed.

Alkali metal sulfites that can be used in preparing the acid hardener fixing baths of the invention include, for example, sodium sulfite, potassium sulfite and ammonium sulfite. Alkali metal bisulfites that can be used in preparing the acid hardener fixing baths of the invention include, cfor example, sodium bisulfite, potassium bisulfite and ammonium bisulfite. The thiosulfates used in preparing the acid hardener fixing baths of the invention are the alkali metal thiosulfates such as sodium thiosulfate, potassium thiosulfate and ammonium thiosulfate, for example. Any suitable harden-ing agent canbe em-' ployed such as potassium alum [K Al (SO .2.4H O'], alum and aluminum chloride, for example. About 3 to about 30 grams of hardening agent per liter are present in the acid hardener fixing baths of the invention. V

A single alkali metal sulfite, such as sodium sulfite, a single alkali metal bisulfite, such as sodium bisulfite, mixtures of alkali metal sulfites, m'nttures of alkali metal bisulfites or mixtures containing both an alkali metal sulfite and an alkali metal bisulfite can be used in preparing the acid fixing baths of our invention. Similarly, a single alkali metal thiosulfate or a mixture of two or more alkali metal thiosulfates' can be employed.

The following examples further illustrate the present invention:

Example 1 Washing 6 Min.

Develtop Fixing oper, 1 Bat h,1 Bath, 3 Min. Min. Min.

Processing Fixing Bath A.

Fixing Bath A Fixing Bath Fixing Fixing Bath A Bath A +Oomposition Residual Hypo: 1

DW Paper E SW Paper 1 Expressed in milligramspcr square inch.

The strips of paper were processed as indicated above trays and then washed on racks in a tank with 68 F. water flowing sufliciently to change the volume once each 2 minutes.

The Fixing Bath A referred to hereinabove and elsewhere has the following composition:

Sodium thiosulfate grams 50.0 Sodium sulfite (desiccated) do 5.0 Acetic acid (28%) cc 16.0 Potassium alum grams" 5.0

Water to make 1 liter of solution.

Composition B referred to hereinabove and elsewhere has the following composition:

Grams Sodium bisulfite 5.0 Sodium sulfite 20.0 Sequestrene NA4 0.5

Example 2 Strips of unexposed Kodak Unicontrast, Grade F, single weight and Kodak Unicontrast, Grade E, double weight photographic paper were processed as in Example 1 except that varying amounts of sodium bisulfite were added to Fixing Bath A in place of sodium sulfite or Composition B. The results obtained are set forth hereinafiter:

Residual Hypo Content (Milligrams per Added Sodium B ulfite (Grams per Liter of Square Inch) Bath A) Fixing SW Paper DW Paper The percentages refer to the added mole percent sodium bisulfite per mole of sodium thiosulfate. It is here noted that Fixing Bath A contains about 12.5 mole percent sodium sulfite per mole of sodium thiosulfate.

The results disclose that sodium bisulfite was very effective in aiding hypo removal from both double weight and single weight paper.

Example 3 Strips of unexposed Kodak Unicontrast, Grade F, single weight and Kodak Unicontrast, Grade -E, double weight photographic paper were processed on a Kodak Model III continuous paper processor. The processing cycles and the results obtained are tabulated hereinafter:

1 Milligrams per square inch. The results show, for example, that the addition of 50 grams of sodium bisulfite per liter of the fixing bath more than compensates for a 50% decrease in the time for the fixing bath and washing operations.

Washing was carried out with 68 F. water, the total flow of water being about 4 gallons a minute, including a spray Wash for 1 minute at the rate of 1.75 gallons per minute.

Example 4 Strips of unexposed Kodak Unicontrast, Grade F, single weight photographic paper were processed on a Kodak Model II'I continuous paper processor. The processing cycles and the results obtained are tabulated hereinafter.

1 Expressed in milligrams per square inch.

The results obtained show, for example, that the addition of 25.5 grams of Composition B per liter of the fixing bath more than compensated for doubling the speed of the processing machine.

Washing was carried out with 68 F. water, the total flow of water being about 4 gallons a minute, including a spray wash for 1 minute at the rate of 1.75 gallons per minute.

Example 5 A sheet of unexposed Kodak Super XX sheet film was developed with Kodak Developer DK-50 for 4 minutes at 68 F., stopped with Kodak Stop Bath SB-l, washed well with water and fixed in Kodak Fixing Bath F-5 diluted with an equal volume of water. Similarly an unexposed sheet of the same film was fixed in the same bath with the addition of grams of sodium bisulfite per liter. After 5 minutes washing the hypo content of the film fixed in the first fixing bath was 0.34 mg. per square inch while that of the film fixed in the modified fixing bath was 0.20 mg. per square inch. Except for the difference in the fixing baths both sheets of film were processed under the same conditions.

Kodak Super XX film is a high speed panchromatic photographic film.

The photographic developer employed in Examples 1, 2, 3 and 4 was essentially Kodak Developer D-52. The development temperature was 68 F. Kodak Fixing Bath F-24 at 68 F. was employed as the stop bath in Examples 1, 2, 3 and 4.

Unless otherwise indicated the term alkali metal as used herein and in the claims includes ammonium.

The term sodium thiosulfate as used herein and in the claims refers to Na S O In some instances the word anhydrous has been inserted after sodium thiosulfate to emphasize that Na S O is intended.

The examples given are illustrative and not limitative of the invention. Thus, for example, other photographic films and papers in addition to those specifically disclosed can be treatal with the acid photographic hardener fixing baths of the invention.

We claim:

1. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of an alkali metal thiosulfate, an aluminum-containing hardening agent and a member selected from the group consisting of an alkali metal sulfite and an alkali metal busulfite, and wherein the total amount of alkali metal sulfite and alkali metal bisulfite present is equivalent to about 60 to about 150 mole percent of alkali metal sulfite per mole of alkali metal thiosulfate, 1 mole percent of alkali metal sulfite being equivalent to 2 mole percent of alkali metal bisulfite, and wherein said acid photographic hardener fixing bath contains an amount of alkali metal thiosulfate equivalent to about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

2. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of an alkali metal thiosulfate, an aluminum-containing hardening agent and an alkali metal sulfite, the alkali metal sulfite being present in the proportion of about 60 to about 150 mole percent per mole of alkali metal thiosulfate and wherein said .acid photographic hardener fixing bath contains an amount of alkali metal thiosulfate equivalent to about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

3. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of an alkali metal thiosulfate, an aluminum-containing hardening agent and an alkali metal bisulfite, the alkali metal bisulfite being present in the proportion of about 120 to about 300 mole percent per mole of alkali metal thiosulfate and wherein said acid photographic hardener fixing bath contains an amount of alkali metal thiosulfate equivalent to about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

4. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of sodium thiosulfate, an aluminum-containing hardening agent and an alkali metal sulfite, the alkali metal sulfite being present in the proportion of about 60 to about 150 mole percent per mole of sodium thiosulfate and wherein said acid photographic hardener fixing bath contains about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

5. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of sodium thiosulfate, an aluminum-containing hardening agent and an alkali metal bisulfite, the alkali metal bisulfite being present in the proportion of about 120 to about 300 mole percent per mole of sodium thiosulfate and wherein said acid photographic hardener fixing bath contains about 40 to about 250 grams of sodium thio sulfate (anhydrous) per liter of solution.

6. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of sodium thiosulfate, an aluminum-containing hardening agent and sodium sulfite, the sodium sulfite being present in the proportion of about 60 to about 150 mole percent per mole of sodium thiosulfate and wherein said acid photographic hardener fixing bath contains about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

7. An acid photographic hardener fixing bath which can be readily Washed out of photographic films and papers after fixing, comprising an aqueous acid solution of sodium thiosulfate, an aluminum-containing hardening agent and sodium sulfite, the sodium sulfite being present in the proportion of about 75 to about 150* mole percent per mole of sodium thiosulfate and wherein said acid photographic hardener fixing bath contains about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

8. An acid photographic hardener fixing bath which can be readily Washed out of photographic films and papers after fixing, comprising an aqueous acid solution of sodium thiosulfate, an aluminum-containing hardening agent and sodium bisulfite, the sodium bisulfite being present in the proportion of about to about 300 mole percent per mole of sodium thiosulfate and wherein said acid photographic hardener fixing bath contains about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

9. An acid photographic hardener fixing bath which can be readily washed out of photographic films and papers after fixing, comprising an aqueous acid solution of sodium thiosulfate, an aluminum-containing hardening agent and sodium bisulfite, the sodium bisulfite being present in the proportion of about to about 300 mole percent per mole of sodium thiosulfate and wherein said acid photographic hardener fixing bath contains about 40 to about 250 grams of sodium thiosulfate (anhydrous) per liter of solution.

10. An acid photographic hardener fixing bath having the following composition:

Sodium thiosulfate grams 50.0 Potassium alum do 5.0 Sodium sulfit do 25.0 Acetic acid (28%) cc 16.0

Water to make 1 liter of solution.

11. An acid photographic hardener fixing bath having the following composition:

Sodium thiosulfate grams 50.0 Potassium alum do 5.0 Sodium sulfite do 55.0 Acetic acid (28%) cc 16.0

Water :to make 1 liter of solution.

12. An acid photographic hardener fixing bath having the following composition:

Sodium thiosulfate grams 50.0 Potassium alum do 5.0 Sodium sulfite 10.... 25.0 Sodium bisulfite do 5.0 Acetic acid (28%) cc 16.0

Water to make 1 liter of solution.

13. An acid photographic hardener fixing bath having the following composition:

Sodium thiosulfate grams 50.0 Potassium alum do 5.0 Sodium sulfite do 5.0 Sodium bisulfite do 60.0 Acetic acid (28%) cc 16.0

Water to make 1 liter of solution.

14. An acid photographic hardener fixing bath having the following composition: 

1. AN ACID PHOTOGRAPHIC HARDENER FIXING BATH WHICH CAN BE READILY WASHED OUT OF PHOTOGRAPHIC FILMS AND PAPERS AFTER FIXING, COMPRISING AN AQUEOUS ACID SOLUTION OF AN ALKALI METAL THIOSULFATE, AN ALUMINUM-CONTAINING HARDENING AGENT AND A MEMBER SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL SULFITE AND AN ALKALI METAL BUSULFITE, AND WHEREIN THE TOTAL AMOUNT OF ALKALI METAL SULFITE AND ALKALI METAL BISULFITE PRESENT IS EQUIVALENT TO ABOUT 60 TO ABOUT 150 MOLE PERCENT OF ALKALI METAL SULFITE PER MOLE OF ALKALI METAL THIOSULFATE, 1 MOLE PERCENT OF ALKALI METAL SULFITE BEING EQUIVALENT TO 2 MOLE PERCENT OF ALKALI METAL BISULFITE, AND WHEREIN SAID ACID PHOTOGRAPHIC HARDENER FIXING BATH CONTAINS AN AMOUNT OF ALKALI METAL THIOSULFATE EQUIVALENT TO ABOUT 40 TO ABOUT 250 GRAMS OF SODIUM THIOSULFATE (ANHYDROUS) PER LITER OF SOLUTION. 